1. Field of the Invention
The present invention generally relates to a device for and a method of tracking a moving object, and more particularly, to a device for and a method of automatically detecting a moving object through signal processing on input images and continuously tracking the moving object until the moving object escapes out of a monitoring area.
2. Description of the Related Art
There are various types of tracking systems worldwide for automatically detecting and tracking a moving object based on input image information.
The following are a few representative examples of tracking methods applied in such tracking systems that track the moving object through the input image information.                1. Tracking based on a difference signal between two frames        2. Tracking based on a correlation (block matching algorithm)        3. Tracking based on a disturbance map        4. Tracking based on a color distribution        5. Tracking based on an optical flow        
Despite some advantages, most of the currently available tracking methods including the above are difficult to commercialize due to problems especially in terms of speed and accuracy.
The Korean Patent Publication No. 10-20010000107 published Jan. 5, 2001 discloses a multi moving object tracking and monitoring system, which is a combined form of various tracking methods.
The multi moving object tracking and monitoring system mainly includes a general monitoring device and a local monitoring device. The general monitoring device has a fixed camera monitoring a wide area, and registers and tracks all the moving object within a predetermined monitoring range. For a certain moving object among the registered moving objects, the general monitoring device transmits a tracking command to the local monitoring device to track the certain moving object, and thus, the local monitoring device keeps tracking the certain moving object until the certain moving object escapes out of the monitoring range.
FIG. 1 is a block diagram showing a local monitoring device of a multi moving object tracking and monitoring system.
A local monitoring device 100 includes a camera 10, an image input unit 20 receiving input signal corresponding to images from the camera 10, an image compensation unit 30 eliminating a noise factor from the input image signal, a motion detecting unit 40 detecting a movement of the moving object based on a disturbance map from the compensated input image signal, a moving object extracting unit 50 separating the moving object from the input image signal, a moving object tracking unit 60 tracking the moving object based on extracted position and speed information of the moving object, and a camera movement compensation unit 70 compensating for the input image signal in accordance with a movement of the camera 10.
An operation of the local monitoring device 100 constructed as above will be described below with reference to a flowchart of FIG. 2.
First, when the images taken by the camera 10 are input to the image input unit 20 in operation S1, the image compensate unit 30 filters the input image signal to eliminate noise factors therefrom in operation S2, and the camera movement compensation unit 70 compensates for the input image signal according to the movement of the camera 10 in operation S3. Next, with respect to the compensated input image signal, the motion detecting unit 40 detects the movement of the moving object through the disturbance map algorithm in operation S4. The moving object extracting unit 50 extracts an actual image of the moving object through division and composition of the images in a motion area extracted through a disturbance map in operation S5. Then, the moving object extracting unit 50 estimates a next location of the moving object by applying the extracted location and speed information of the moving object to an estimating algorithm that uses a Kalman filter, and then tracks the moving object in operation S6. When the moving object stops and thus there is no further movement, or when it becomes hard to track the moving object because many objects crossed one another, the tracking is continued by using a block matching process in operation S7. As the movement of the moving object is detected, the camera 10 is moved in accordance with the movement of the moving object in operation S8. After that, the tracking of the moving object includes repeating the above processes.
In this multi moving object tracking and monitoring system, many algorithms are used, and among them, the disturbance map algorithm is representative example that is used to automatically acquire or extract the information about the moving object. For the purpose of the tracking of the moving object, a block matching algorithm is used.
In a conventional moving object tracking system, an extracting performance based on a disturbance map algorithm is satisfactory when a camera is in a static state. However, when the camera is in motion, image compensation is inevitably required. For this purpose, the conventional art uses a camera compensation algorithm, which results in an increased amount of data to be processed by the system and consequent overload in data processing.
A block matching algorithm, which has been used for tracking the moving object, also degrades a data processing speed because a size of a block increases as the moving object is moved, and because the size, shape or brightness changes.